Sympathetic nerves protect the blood-brain barrier in stroke-prone spontaneously hypertensive rats

Disruption of the blood-brain barrier may play a major role in the pathogenesis of hypertensive encephalopathy. In this study we determined whether sympathetic nerves to cerebral vessels protect the blood-brain barrier during chronic hypertension. We removed the cervical sympathetic ganglion on one side in 24 stroke-prone hypertensive rats when they were 1 month old. After signs of cerebral dysfunction developed at the mean age of 160 +/- 5 days (SE), we injected 125I-albumin and Evans blue dye intravenously to evaluate the permeability of the 125I-albumin was 3.53 +/- 0.83 (brain albumin x 100/blood albumin) in areas of the cerebrum stained with blue dye and 0.24 +/- 0.02 in unstained areas (p less than 0.05). We conclude that sympathetic nerves protect the blood-brain barrier against disruption during chronic hypertension and thereby may protect against hypertensive encephalopathy.